The proposed work will involve a study of the control of one-carbon metabolism in the bacterium, Pseudomonas MA. These studies will be focused on the allosteric properties of the enzyme, phosphoenolpyruvate carboxlase, which has been found to be activated by reduced nicotinamide adenine dinucleotide (NADH) and inhibited by adenosine diphosphate (ADP). The molecular weight forms of the native enzyme, the NADH activated form of the enzyme, and the ADP inhibited enzyme will be studied by sedimentation equilibrium centrifugation, and by kinetic studies. In addition, the relationship of the induced NADH activated PEP carboxylase to the constitutive acetylCoA dependent enzyme will be studied by comparing the similarities in subunits of the two enzymes. A similar comparison will be made between the methylamine induced malate thiokinase and the constitutive succinate thiokinase. These studies will include the preparation of antibody directed against each of the enzymes, and a comparison of their cross-reactivity. In addition, the subunits will be prepared and compared to each other by proteolytic digestion followed by peptide mapping. BIBLIOGRAPHIC REFERENCES: Louis B. Hersh, "Growth of Pseudomonas MA on Methylamine" Microbial Growth on C-1 Compounds 73-80 (1975). Marilyn Schuman Jorns and Louis B. Hersh, "N-Methylglutamate Synthetase: Substrate-Flavin Hydrogen Transfer Reactions Probed with Deazaflavin Mononucleotide", Journal of Biological Chemistry, 250, 3620-3628 (1975).